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REPORT
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Publication Number:  FHWA-HRT-14-021    Date:  January 2014
Publication Number: FHWA-HRT-14-021
Date: January 2014

 

Screening Level Assessment of Arsenic and Lead Concentrations in Glass Beads Used in Pavement Markings

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FOREWORD

This report provides results of an assessment of the potential risk to human health posed by occupational and residential exposure to arsenic and lead concentrations found in glass beads used in pavement markings. The study used glass beads from samples of inventories from 15 State transportation departments to ascertain minimum screening levels based on both carcinogenic and noncarcinogenic effects, with the lower value selected as the final recommended screening level. The recommended screening levels were determined to be 220 ppm for arsenic, based on the child resident scenario, and 580 ppm for lead, based on the worker scenario. These determined screening levels are greater than the maximum content of 200 ppm for arsenic and 200 ppm for lead in glass beads prescribed in MAP-21 (the Moving Ahead for Progress in the 21st Century Act); therefore, the values specified in the existing legislation are considered protective of health based on currently available data.

The report is divided into three sections. The first section provides a detailed characterization of arsenic and lead concentrations in commercially available glass beads in current use on U.S. roadways, including the total, extractable, and bioaccessible arsenic and lead content in glass bead samples provided by State transportation departments. The second section describes the modeling methodology used to estimate the potential for adverse human health effects associated with arsenic and lead in glass beads used in pavement markings. The third section provides the human health screening levels for arsenic and lead in glass beads that are considered protective of human health. The results of the screening level assessment indicate that currently available products pose minimal health risk to humans while meeting retroreflective performance criteria.

Monique R. Evans
Director, Office of Safety
Research and Development

Notice

This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

 

Technical Report Documentation Page

1. Report No.

FHWA-HRT-14-021

2. Government Accession No.

 

3. Recipient’s Catalog No.

 

4. Title and Subtitle

Screening Level Assessment of Arsenic and Lead Concentrations in Glass Beads Used in Pavement Markings

5. Report Date

January 2014

6. Performing Organization Code:

7. Author(s)

Bryan Boulanger, Paul Carlson, Harry Fatkin, and Aditya Raut-Desai

8. Performing Organization Report No.

9. Performing Organization Name and Address

Texas A&M Transportation Institute

The Texas A&M University System

College Station, Texas 77843-3135

10. Work Unit No.

TRAIS

11. Contract or Grant No.

DTFH68-09-E-00105

12. Sponsoring Agency Name and Address

Office of Infrastructure Research & Development

Federal Highway Administration

6300 Georgetown Pike

McLean, VA 22101-2296

13. Type of Report and Period Covered

Final Report

14. Sponsoring Agency Code

 

15. Supplementary Notes

Projects were performed with the cooperation and participation of the Environmental Protection Agency
Project Title: Development of Roadway Guidance Information

16. Abstract

Retroreflective glass beads used in pavement markings are a critical component of highway safety. Glass beads meeting American Association of State Highway and Transportation Officials (AASHTO) M247 specifications are the current industry standard. AASHTO M247 glass beads are fabricated using reclaimed glass cullet, offering cost effective performance while beneficially reusing sources of industrial and commercial waste glass. However, reclaimed glass cullet may contain elevated levels of arsenic and lead that can be passed through to the final product. Concern regarding the presence of arsenic and lead in retroreflective glass bead products within the U.S. marketplace resulted in recently adopted legislation that sets a 200 part-per-million (ppm =
106 x massmetal/massbeads) limit for both arsenic and lead for beads used on U.S. roadways. While the scientific justification for the 200 ppm limit is not immediately clear, the proposed legislation is regarded as a good-faith attempt to limit the risk associated with the presence of arsenic and lead in the beads.

This research developed a preliminary understanding of the risk associated with the presence of arsenic and lead in glass beads used in pavement marking systems to support decisionmaking. Researchers tested 15 samples of commercially available glass beads in current use on U.S. roadways from State transportation department stockpiles. The mean total concentration observed in the sampled beads across replicates was 71 ppm arsenic and 54 ppm lead. Extractable and bioaccessible arsenic levels in the beads were below instrument detection limits, and extractable and bioaccessible levels of lead in the beads were present at less than 3.6 ppm as a maximum mean value. Based on laboratory-generated characterization data, field investigations, available literature data, and the developed model, reasonably conservative screening levels for arsenic and lead in glass beads were determined to be 220 ppm and 580 ppm, respectively. Lead and arsenic levels observed in glass bead samples provided by State transportation departments were within the determined screening limits, indicating that currently available products pose minimal health risk while meeting retroreflective performance criteria.

17. Key Words

Pavement markings, glass beads, health, human health, environment, risk assessment, arsenic, lead, retroreflectivity, extractable, bioaccessible

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

92

22. Price

 

Form DOT F 1700.7 (8-72)                                                                                             Reproduction of completed page authorized

 


 

SI* (Modern Metric) Conversion Factors

Table of Contents

Executive Summary

Aim 1: Characterization of Arsenic and Lead Concentrations in Commercially Available Glass Beads in Current use on U.S. Roadways

Aim 2: Screening Level Risk Assessment to Assess the Impacts of Occupational and Residential Exposure to Arsenic and Lead within Glass Beads.

Section 1. Characterization of Arsenic and Lead Concentrations within Commercially Available Glass Beads in Current Use on U.S. Roadways.

Introduction

Experimental Methods

Results and Discussion

Conclusions.

Section 2. Proposed Model for the Assessment of Human Health Risks Associated with Glass Beads Used for Pavement Marking

Introduction

Exposure Assessment

Exposure Pathways

Migration Pathways

Modeling Methods

Section 3. Model-Derived Human Health Screening Levels For Arsenic And Lead In Glass Beads.

Introduction..

Risk Evaluation Results

Guidance for DecisionMaking

Acknowledgments

References


List of Figures

 

 


List of Tables

 


List of Abbreviations

AAS                            Atomic Absorption Spectroscopy

AASHTO                    American Association of State Highway and Transportation Officials

ACS                            American Chemical Society

AGBMA                     American Glass Bead Manufacturing Association

ALM                           Adult Lead Model

ATSDR                       Agency for Toxic Substances and Disease Registry

ATV                            All-Terrain Vehicle

BDL                            Below the Detection Limit

BQL                            Below the Quantitation Limit

CFR                            Code of Federal Regulations

CSEM                         Conceptual Site Exposure Model

CSL                             Cancer Screening Level

DAF                            Dilution-Attenuation Factor

DI                                Deionized

EPA                            Environmental Protection Agency

FDOT                          Florida Department of Transportation

FHWA                        Federal Highway Association

FP-XRF                      Field-Portable XRF

GW SL                        Groundwater Screening Level

HI                                Hazard Index

HPLC                          High Performance Liquid Chromatography

HQ                              Hazard Quotient

ICP-MS                       Inductively Coupled Plasma-Mass Spectrometry

IEUBK                       Integrated Exposure Uptake Biokinetic Model

ILCR                           Incremental Lifetime Cancer Risk

KOH                           Potassium Hydroxide

MAP-21                      Moving Ahead for Progress in the 21st Century Act

MDL                           Method Detection Limit

NCSL                          Non-Carcinogenic Screening Level

NIST                           National Institute of Standards and Technology

NJIT/RU                     New Jersey Institute of Technology/Rowan University

NRMRL                      National Risk Management Research Laboratory

PEF                             Particulate Emission Factor

PNNL                         Pacific Northwest National Laboratory

PQL                            Practical Quantitation Limit

QA/QC                       Quality Assurance/Quality Control

RSL                             Regional Screening Level

SRM                            Standard Reference Material

TAMU                        Texas A&M University

TFHRC                       Turner-Fairbanks Highway Research Center

TTI                              Texas A&M Transportation Institute

UCL95%                     95-Percent Upper Confidence Limit

XRF                            X-Ray Fluorescence


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